ExS can calculator standard basic math and solve complex math expressions. Everything is entered in on one line (or use the mouse) and all input and output is kept in memory through the calculator's scrollable display. You can even export your work to .RTF (rich text format) for later editing and printing to paper. You can also assign expressions to a button for quick evaluations using the same formula. ExS also remembers the last answer to any problem and allows you to bring it up instantly. This is a complete Windows Calculator replacement.